The present invention relates generally to gas turbine engines and more particularly to cooling a turbine airfoil.
In operation, turbine airfoils are routinely exposed to temperatures well above their material limits. In existing engines, air from the compressor section of the turbine engine is used to cool the airfoil. Cast-in passages, known as minicores, are embedded in the airfoil wall to enhance convective cooling. Because of the high heat fluxes associated with these cooling circuits, large thermal gradients arise and the airfoil becomes susceptible to thermal mechanical fatigue cracking. To reduce thermal strains, a web is required between the minicores to stiffen the airfoil wall. The presence of the web, however, creates an area of lower heat flux compared to that of the adjacent minicores.